Rising Damp Problem

Podger23

I got some rising damp coming up through a concrete floor which has no/damaged damp proofing. The entire area is 40 sqm 30 sqm is concrete flooring the other 10 sqm is wooden which will need to be replaced with concrete. Instead of ripping up the 30 sqm of concrete and laying a whole new floor which would be ideal. Could I lay the new 10 sqm area of concrete minus the screed as in the diagram then use liquid damp proofing overlaid with a rubber damp proofing sheet for the entire area then screed the whole area taking into account that the 10sqm area will have 2 damp proofing layers and that the rubber damp proofing will also go up the walls by a meter or so. Will this work Id appreciate any advice especially if you have used the liquid damp proofing before. Also if this is not an option does anyone have a rough estimate for laying a entire new floor. If I was to do it myself or get a contractor.
Cheers

bozd

dont know about the floor stuff but is the house old? if it is stone I have seen the damp go to the second floor where the damp proof stopped - it may wick up the wall. similarly friends had to strip off external plaster because water trapped behind concrete plaster cracks letting it in going into house so its always good to know where its coming in or up.

restoring a stone farmhouse myself, walls built on ground, no foundation. took out concrete floor myself as was soaking up the damp - have been looking at 'the oldbuilders'???? site - google limemortar or irish cottage restoration and you can find them. shows how they did floors - worth a look.

have not replaced floor yet but need to save up the money for it.:(

best of luck with the project

Spread

If I was doing this, I'd hack the plaster off the walls to 1m high. Then clean out the sub floor and prepare it with hardcore/2"down/coarse sand. Lay 1000 guage polythene and up to 6" above the concrete level - making sure not to puncture it. Lay scaffold boards (or something similiar) flat along the floor and against the wallsat concrete finish height and secure so they don't float. Pour the conctrete and leave for a couple of days. Then remove the scaffold boards so you have a rebate of 12" X 2" around the edges. Cut back the wall polythene to an inch above the concrete and give the walls a coat of 3:1 (washed sand) plus waterproofer. It doesn't have to be straight - just once it is all covered and smooth. (This is so it will accept the blackjack and not have any voids). You fill in the track in the floor with the same and float it level. At the meeting of the floor and wall use a bottle to bull nose the joint. This is important. Then you can blackjack the lot following the product's instructions. I presume you are going to dry-line the walls. If not, then float out level and when you're skimming keep the skim coat 2 or 3" above the height of the finished screed/timber.